The invention relates to an inflatable roof for a vehicle, particularly a passenger car, which, in the inflated condition, extends between a windshield frame and a rear area of the vehicle body, the roof being divided into a plurality of air chambers.
In the case of a known inflatable roof of the initially mentioned type (U.S. Pat. No. 3,227,486), the whole roof area is divided into adjacent, longitudinally directed air chambers which are constructed in a tube shape, in which case the roof is constructed as a two-chamber system so that, in the case of a defect of one air chamber, the function of the roof is maintained at least to a limited degree. The air chambers of the two chamber systems in this case have the same operating pressure.
Because of the shell-side grooves between the respective adjacent air chambers, this roof has no smooth-surface shell, whereby the drag coefficient is increased. In addition, there is the problem that, although when the air chambers are inflated tautly, a sufficient stiffness of the roof is achieved, in the case of such an inflating, the roof swells up in the manner of a balloon, which is not desirable.
It is an object of the invention to further develop an inflatable roof in such a manner that, while the drag coefficient is acceptable, a sufficient stiffness of the roof is achieved and that, in addition, a balloon-type swelling-up of the roof is avoided.
According to the invention, this object is achieved by means of an arrangement wherein an inflatable roof for a vehicle, particularly a passenger car which extends in the inflated condition between a windshield frame and a rear area of the vehicle body, the roof being divided into a plurality of air chambers, wherein the roof has air chambers with different operating pressure levels.
The principal advantages achieved by means of the invention are that, by means of the development of a frame or supporting structure with a relatively high operating pressure and by means of zones which are situated in-between and have a significantly lower operating pressure, an inflatable roof is provided which has sufficient stiffness and which, in the process, does not swell up in the manner of a balloon. In addition, the charging time is reduced as a result of the different operating pressures in the individual air chambers. The shape of the roof is determined by the frame or supporting structure; the areas situated in-between only have a shape-supporting effect.
By means of the arrangement of additional shaping elements, the dimensional stability of the roof is increased further. The bead-type end areas of the circumference-side first air chamber of the frame or supporting structure permit, in connection with the undercut receiving devices on the windshield frame and in the rear area, a simple fastening of the roof on the vehicle body. In the evacuated condition the roof can be stored, in a rolled-up state, in a relatively small storage compartment of the rear area.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.